Read most importantly the LIST OF INGREDIENTS! This is where you find out whether the thing you're buying is actually food. All the ingredients should sound like something you could eat or cook. If it doesn't sound like food, it ain't food. If it doesn't grow, or run, or swim, or fly, it ain't food. Very simple. I personally don't like consuming non-foods, and don't think they're healthy.
As far as the nutrient information, compare it to the serving size, see if the serving size makes sense. E.g., nobody eats 1/2 cup pasta - it's more like 2 cups. That makes a difference in the amounts of nutrients ingested.